Apparatus for rotary drilling

ABSTRACT

An improved rotary drilling apparatus is provided in which an auxiliary drive member is connected in the pipe string below the kelly for selective engagement with the rotary table permitting uninterrupted drilling operations for approximately the combined length of the kelly and auxiliary drive member. The invention is particularly useful in washover drilling for fish removal since the apparatus makes possible the addition of extra lengths of drill pipe to the pipe string without disengaging the washover pipe drill from around the fish. This abstract is neither intended to define the invention of the application, which of course is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

States Patent 11 1 West Nov. 19, 1974 APPARATUS FOR ROTARY DRILLING 3,722,608 3/1973 Faulk 175/107 x [75] Inventor: Thomas Douglas West, l-louma, La.

Primary Examiner-David H. Brown [73] Asslgnee: s Indusmes, Attorney, Agent, or FirmW. Ronald Robins; Joe E.

Bossier Pansh, La. Edwards [22] Filed: Aug. 2, 1973 211 Appl. No.1 385,171 7] AB TRA An improved rotary drilling apparatus is provided in 52 US. Cl 175/195, 64/235, 173/165, which an auxiliary drive member is connected n the 175/321 pipe string below the kelly for selective engagement 151 Int. Cl E2lb 17/00 with the rotary table permitting uninterrupted drilling [58] Fi ld f S a ch 64/235, 23; 175/195, 170 operations for approximately the combined length of 175/207, 321, 320, 107; 173/165 the kelly and auxiliary drive member. The invention is particularly useful in washover drilling for fish re- [56] References Cit d moval since the apparatus makes possible the addition Of extra lengths Of t0 the string WlthOLlt disengaging the washover pipe drill from around the l,844,257 2/1932 Lincoln 64/23 fish- This abstract is neither intended to define the 2,107,475 2/l938 Foster... 175/195 2,222,207 11/1940 Teis et al. 64/235 "emlon of the F 'P; f of [i 2,286,593 6/1942 Abegg 64/235 sured by the clams, 15 It Intended to be llmlllng as 3,038,547 6/1962 Deely .3 l73/l65 x t0 the Scope of the invention in y y- 3,255,6l2 6/1966 Mayer et al 1 64/235 3,319,726 5/1967 Brown 175/5 5 Clalms, 4 Drawmg Flgures PATENTEL YQUV 1 91974 O AY APPARATUS FOR ROTARY DRILLING SUMMARY OF THE INVENTION This invention relates to improvements in rotary drilling and particularly to an improved method and apparatus for washover drilling around a section of pipe stuck in a wellbore to effect its release and retrieval.

An object of the present invention is to provide a method and apparatus for washover drilling for fish removal in which the washover pipe drill, onceit has been engaged in telescoping relationship with the fish, need not be raised out 'of engagement with the fish in order to add additional lengths of drill pipe.

Another object is to provide a rotary drilling apparatus which can be operated to drill for a depth greater than the operative length of the kelly before being raised for the insertion of an additional length of drill pipe.

Another object is to provide a rotary drilling apparatus having an auxiliary drive member disposed below the kelly and adapted for selective engagement with the rotary table whereby the apparatus may be operated to drill for approximately the length of the auxiliary drive member plus the length of the kelly before being raised for the insertion of additional drill pipe between the auxiliary drive member and the kelly.

Another object is to provide a method for washover drilling for fish removal in which an auxiliary drive member is employed below the kelly whereby the washover pipe drill may drill around the fish to a depth equal to the length of the kelly plus that of the auxiliary drive member, after which the pipe string is raised only for the length of the kelly to permit the insertion of an additional length of drill pipe so that the washover pipe once engaged about the fish need not be disengaged until the washover operation is completed.

DESCRIPTION OF THE DRAWINGS AND PREFERRED EMBODIMENTS These and other objects and advantages of the invention will become apparent from the drawings, the specification and claims. In the accompanying drawings, which illustrate the preferred embodiment of the invention, and wherein like numerals indicate like parts:

FIG. 1 is a somewhat diagramatical illustration, in elevation and partly in section, of a conventional prior art rotary drilling apparatus used in washover drilling for fish removal;

FIG. 2 is a view similar to FIG. 1 showing the conventional washover drilling apparatus modified according to the present invention by the addition of an auxiliary drive member and related apparatus;

FIG. 3 is a plan view, partly in section, taken along line 3-3 of FIG. 2 showing details of the preferred form of split bushing used to engage the auxiliary drive member with the rotary table;-and

FIG. 4 is a diagramatical illustration in elevation of the drilling sequence performed utilizing the apparatus of the present invention.

Referring to FIG. 1 there is shown a conventional rotary drilling apparatus utilized in washover drilling operations to drill around and free a pipe or fish l stuck in a wellbore 12 by debris-14. At the wellhead is provided the usual derrick 16 having draw works 18 and swivel 20 from which is suspended the drill string 22 comprising all the apparatus suspended from the swivel. At the uppermost end of the drill string is the usual kelly 24. The kelly 24 includes two end portions 26 which are circular in cross-section and contain treads for connecting the kelly into the drill string 22. Extending between the two end portions 26 is an elongated drive section 28 of noncircular external crosssectional configuration. The most common crosssectional kelly configurations are hexagonal, as shown, and square, although other configurations are of course possible. Extending longitudinally through the kelly is a bore (not shown) for drilling fluid circulation.

Slidably disposed about the drive section 28 of kelly 24 is the kelly drive bushing 30 which provides means for selectively engaging the kelly with the rotary table. Extending longitudinally through the kelly drive bushing 30 is an opening of the same cross-sectional configuration as the drive portion 28 of kelly 24. Kelly drive bushing 30 may therefore slide longitudinally along the drive section 28 but may not rotate with respect to the kelly. The external surface of drive bushing 30 is also noncircular in cross-section and adapted to seat within a corresponding noncircular recess 32 in the rotary table 34. Thus the kelly drive bushing 30 when seated within recess 32 of rotary table 34 serves to engage the kelly 24 with the rotary table for rotation therewith. Suitable machinery (not shown) is provided for driving the rotary table.

Disposed below and releasably connected to the kelly 24 is a pipe string 36 made up of aplurality of drill pipe sections 38. The pipe string 36 terminates in a washover pipedrill40 comprising an elongated cylindrical washpipe 42 having an internal'bore-of sufficient diameter to accommodate the fish l0 and a drill 44 of the same cross-sectional configuration as wash pipe 40, but having teethor serrations 44a adapted to drill outthe debris l4 bindingthe fish 10 in the well.

In operation, the washover pipe drill 40 is lowered on the drill string intoa telescoping relationship with the fish, whereby the upper end of fish 10 is disposed within the bore of washover pipe drill 40. Kelly 24 is then engaged withthe rotary table 34 by means of the kelly drive bushing 30 whereby the entire drill string 22 comprising the kelly, pipe string, and washover pipe drill are rotated to drill circumferentially around the fish l0. Simultaneously drilling fluid is circulated down through the bores of kelly 24, the drill pipe sections 38 and the washover pipe drill 40 to flush out the drilled debris and carry it back up the well annulus to the surface.

A problem frequently encountered in this fishing operation is illustrated in FIG. 1. As there shown, the top of the fish is disposed at an angle with respect tothe wellbore so that the washover pipe drill cannot readily be lowered into telescoping relationship with the fish. Under these circumstances, considerable time and-effort may be required to get the washover pipe drill placed about the fish so that washover drilling may begin. However, once this is accomplished and drilling progresses, the kelly is gradually lowered through drive bushing 30. When the upper end of the drive section 28 is reached, it is necessary to pick up the entire drill string 22 to add an additional length of drill pipe to the top of the drill string below the kelly. This operation results in the washover pipe drill being lifted out of telescoping relationship with the fish. Then, after the additional drill pipe is inserted, it is once again necessary to telescope the washover pipe drill 40 over the fish.

Moreover, due to the addition of the length of drill pipe, this second telescoping operation must be accomplished without rotation, since the lower end of the kelly will be above the rotary table when the washover pipe drill reaches the fish. Without the capability of rotation, the second telescoping may prove even more difficult and time consuming than the first.

Referring now to FIG. 2, there is shown the apparatus of the present invention whereby the second telescoping operation discussed above may be completely eliminated with resulting savings of time and expense. As shown, the usual or prior art rotary drilling apparatus has been modified by the addition of an auxiliary drive member 46 disposed below and releasably connected to the kelly and adapted, as shown below, to form a part of the pipe string. Auxiliary drive member 46 includes upper and lower end portions 48 which are circular in cross-section and contain threads for connecting the auxiliary drive member to the lower end of kelly 24 and to the uppermost joint of drill pipe 38. Extending longitudinally between the two end portions 48 is the drive section 50. The drive section 50, which is of noncircular cross-sectional configuration, may be of the same configuration as the drive section of the kelly 24. Extending longitudinally through the auxiliary drive member is a bore 51 (FIG. 3) for circulation of drilling fluid. The auxiliary drive member is preferably somewhat shorter than the conventional kelly, but may be of any desired length.

Means are provided for selectively engaging the auxiliary drive member 46 with the rotary table 34 for rotation therewith. In the preferred embodiment, the selective engagement means comprise split bushings 52 adapted to be removably disposed about the drive section 50 of auxiliary drive member 46. As shown in greater detail in FIG. 3, the split drive bushings are formed in two sections 52a and 52b. Each section forms one-half of the longitudinal opening 54 of the same cross-sectional configuration as the drive section 50 of the auxiliary drive member. The outside configuration of the splitbushings is such that they may be received within the recess 32 of the drive table 34 to thereby selectively engage the auxiliary drive member with the'rotary table. Two latch pins 56, each having a locking toggle 58 are received within opposed horizontal bores 60a and 60b in the two halves of split bushings 52 to releasably lock the bushings in place around the auxiliary drive member.

For reasons described hereinafter, it is preferable to include in the pipe string 36 below the auxiliary drive member a lost motion connection which will permit limited vertical movement of the upper portion of the drill string 22, including kelly 24 and auxiliary drive member 46 with respect to the lower portion of the drill string including the washover pipe drill 40. As shown in FIG. 2, the lost motion connection means may comprise a conventional bumper jar 62 having upper and lower telescoping sections 62a and 62b. The two sections may be of noncross-sectional configuration, or may be slotted or keyed as desired, to provide for the transmission of rotational movement through the connection.

In drilling with the apparatus of the present invention, once the washover pipe drill has been telescoped over the fish, it'need not be removed from telescoping relationship until the entire fishing operation has been completed. In operation, the pipe string would be lowered in the usual manner until the bottom of the washover pipe drill 40 contacted the fish. If the washover pipe drill can readily be placed in telescoping position around the fish, washover operations would proceed in the usual manner and there would be no particular need for use of the modified apparatus of the present invention. If, however, initial attempts to place the washover pipe drill around the fish are unsuccessful, so that it appears that telescoping will be difficult, then the pipe string is raised, the top joint of drill pipe 38 is removed and the auxiliary drive member 46 is placed in the drill string below the kelly. The drill string is then lowered until the lower end of the drive section 50 of the auxiliary drive member is in a position to be engaged with the rotary table. The split bushings 52 are then placed around the drive section 50 of auxiliary drive member 46 and received within recess 32 of the rotary table 34 to engage the auxiliary drive member with the rotary table. The entire drill string including washover pipe drill 40 is then rotated by means of the auxiliary drive member and drilling fluid is flushed down through the bore of the string in the usual manner, as the string is lowered to telescope the drill over the fish.

When the washover pipe drill has been successfully telescoped over the fish, washover drilling is continued until the top of drive section 50 of the auxiliary drive member 46 reaches the split drive bushings 52. The split drive bushings are then removed from around the auxiliary drive member. The drive sections of the auxiliary drive member 46 and kelly 24 are separated by the length of the connecting end portions 26 and 48. Since the end portions are round, they are not engagable with the rotary table and are lowered through the rotary table 34 without rotation of the drill string. This is most easily accomplished by means of the lost motion connection 62 preferably provided in the pipe string below the auxiliary drive member 46 to facilitate engagement of the drive section of the kelly with the rotary table. The lost motion connection 62, if disposed in the upper portion of the pipe string will be maintained under tension with the telescoping section 62a and 62b extended as shown in FIG. 2. The telescoping length of the lost motion connection 62 is preferably at least as great as the distance between the upper end of the drive section 50 of auxiliary drive member 46 and the lower end of drive section 28 of the kelly 24. The kelly and auxiliary drive member may therefore be lowered by the draw works 18 to lower the abutting end portions 26 and 48 through the rotary table to place the lower end of the kelly drive section 28 in a position to be engaged with rotary table. The kelly may be engaged with the rotary table by means of the usual kelly drive bushing 30 ordinarily disposed about the kelly or, if preferred, the kelly drive bushing 30 may be disposed with and the split drive bushings 52 utilized for driving both the auxiliary drive member 46 and the kelly.

Once the kelly has been engaged with the rotary table, drilling operations are resumed until the length of the kelly has been drilled down and the upper end of drive section 28 of the kelly has reached the top of the kelly drive bushing. The drill string is then raised the length of the kelly and a new joint of drill pipe 38 is added to the pipe string between the kelly and the auxiliary drive member 46.

During this operation, the auxiliary drive member remains in the pipe string and the washover pipe drill remains in telescoping relationship with the fish 10. As illustrated somewhat diagramatically in FIG. 4, the washover drill pipe, when it has been drilled down the length of the auxiliary drive member will be telescoped over the fish and will have reached the depth A. Drilling down the additional length of the kelly will place the bottom of the drill at a lower depth B. Then, when the drill string is raised to add a new joint of drill pipe between the kelly and the auxiliary drive member, the bottom of the washover pipe drill will only be raised back to point A and will remain in telescoping relationship with the fish. The auxiliary drive member remains in place and, in effect, becomes a part of the pipe string, moving progressively farther down in the hole as new joints of drill pipe are added to the top of the pipe string.

While the method and apparatus of the invention have been described principally in connection with washover drilling operations, they may also have application in other drilling situations wherein it is desired to drill in one operation, without raising the drill string, for a depth greater than the length of the kelly.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims, without departing from the spirit of the invention.

What is claimed is: 1. In a rotary drilling apparatus of the type wherein a rotary table imparts rotation to a pipe string and drill through a kelly releasably connected to the upper end of the pipe string and selectively engagable with the table for rotation therewith, the improvement comprismg:

an auxiliary drive member disposed below and releasably connected to said kelly and adapted to form a part of the pipe string, and

means for selectively engaging said auxiliary drive member with said rotary table for rotation therewith.

2. The apparatus of claim 1 wherein said selective engagement means comprise split bushings adapted to be removably disposed about said auxiliary drive member.

3. The apparatus of claim 1 wherein said kelly and said auxiliary drive member each have a noncircular drive section operatively engagable with said rotary table, the said two drive sections being spaced apart by the abutting end portions of said auxiliary drive member and said kelly, the said end portions not being operatively engagable with said rotary table, and comprising additionally,

lost motion connection means in said pipe string below said auxiliary drive member whereby the nonengagable abutting end portions of said auxiliary drive member and said kelly may be lowered through said rotary table to facilitate engagement of the drive section of said kelly with said rotary table.

4. A rotary well drilling apparatus comprising:

a rotary table,

a kelly,

an auxiliary drive member below said kelly,

a pipe string below said auxiliary drive member extending into the bore of a well,

a washover pipe drill at the lower end of said pipe string,

lost motion connection means in said pipe string below said auxiliary drive member permitting limited vertical movement of said kelly and said auxiliary drive member to facilitate engagement of said kelly with said rotary table, and

means for selectively engaging first said auxiliary drive member and then said kelly with said rotary table for rotation therewith.

5. The apparatus according to claim 4 wherein said selective engagement means comprise split bushings adapted to be removably disposed about said auxiliary drive member and rotary drive bushings disposed about said kelly. 

1. In a rotary drilling apparatus of the type wherein a rotary table imparts rotation to a pipe string and drill through a kelly releasably connected to the upper end of the pipe string and selectively engagable with the table for rotation therewith, the improvement comprising: an auxiliary drive member disposed below and releasably connected to said kelly and adapted to form a part of the pipe string, and means for selectively engaging said auxiliary drive member with said rotary table for rotation therewith.
 2. The apparatus of claim 1 wherein said selective engagement means comprise split bushings adapted to be removably disposed about said auxiliary drive member.
 3. The apparatus of claim 1 wherein said kelly and said auxiliary drive member each have a noncircular drive section operatively engagable with said rotary table, the said two drive sections being spaced apart by the abutting end portions of said auxiliary drive member and said kelly, the said end portions not being operatively engagable with said rotary table, and comprising additionally, lost motion connection means in said pipe string below said auxiliary drive member whereby the nonengagable abutting end portions of said auxiliary drive member and said kelly may be lowered through said rotary table to facilitate engagement of the drive section of said kelly with said rotary table.
 4. A rotary well drilling apparatus comprising: a rotary table, a kelly, an auxiliary drive member below said kelly, a pipe string below said auxiliary drive member extending into the bore of a well, a washover pipe drill at the lower end of said pipe string, lost motion connection means in said pipe string below said auxiliary drive member permitting limited vertical movement of said kelly and said auxiliary drive member to facilitate engagement of said kelly with said rotary table, and means for selectively engaging first said auxiliary drive member and then said kelly with said rotary table for rotation therewith.
 5. The apparatus according to claim 4 wherein said selective engagement means comprise split bushings adapted to be removably disposed about said auxiliary drive member and rotary drive bushings disposed about said kelly. 